The present invention generally relates to surface mounted integrated circuit (IC) devices, and more particularly to achieving a solderless connections between a leadless IC device and a printed circuit (PC) board. The invention finds particular application in connection with the burn-in and test of leadless IC devices such as used with ball grid array (BGA) surface mount techniques.
The increased capabilities of IC chips have led to increased input/output (I/O) densities and alternative techniques for surface mounting IC chips to printed circuit (PC) boards involving leadless IC chips. For example, BGA mounting techniques have been developed to replace pin grid array (PGA) mounting approaches in order to achieve more densely packed contacts and smaller contact dimensions (in the order of 25 mils.). To facilitate the testing and burn-in such IC devices, special test sockets have been devised to hold these devices and to temporarily connect them to a PC test board. Test sockets for leadless IC devices most commonly employ stamped or formed metal contact pins for achieving electrical interconnection between the I/O contacts of the IC device being tested and the PC test board circuits. Such socket designs have a relatively high profile and relatively high capacitance and inductance making them undesirable for high speed applications. They also require soldering of the socket pins to the PC board and do not operate efficiently with IC devices having non-compliant I/O contacts. Sockets having elastomeric contactors which do not require soldering have also been devised. These sockets utilize flexible wire filaments which extend in a perpendicular relation to the contact points. Such wire filaments are generally not reliable and will not hold up with repetitive use. In addition, they are not likely to withstand the thermal shock encountered while testing an IC device.
The present invention overcomes the disadvantages of conventional sockets for leadless IC devices by providing a solderless electrical interconnection between a PC board and the IC device which is suitable for high frequency circuits, which will operate at extreme temperatures, and which withstands repeated insertions and extractions of the IC device from the IC socket. While the invention is particularly suited to use with sockets for test and burn-in procedures, it can be used in any application requiring the surface mounting of a leadless IC device to a PC board.